Submission #1274589

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274589		quanduongxuan12	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	792 ms	104520 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define name "tracks"
#define MAXN 4003
#define pb push_back
#define pf push_front
#define ll long long
#define ii pair<int, int>
#define fs first
#define sc second
#define ill pair<int, ll>
#define lli pair<ll, int>
#define llll pair<ll, ll>
#define all(v) v.begin(),v.end()
#define uni(v) v.erase(unique(all(v)),v.end())
#define bit(n,i) (((n)>>(i))&1)
#define FOR(i,a,b) for (int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for (int i=(a),_b=(b); i>=_b; i--)
#define MASK(i) (1LL<<(i))
const int INF=1e9;
const int MOD=1e9+7;
void add(int &u, int v){
    u+=v;
    if (u>=MOD) u-=MOD;
}
void sub(int &u, int v){
    u-=v;
    if (u<0) u+=MOD;
}
void minimize(int &u, int v){
    u=min(u,v);
}
void maximize(int &u, int v){
    u=max(u,v);
}
long long Rand(long long l, long long r){
    ll tmp=0;
    FOR(i,1,4) tmp=((tmp<<15)^(((1<<15)-1)&rand()));
    return l+tmp%(r-l+1);
}
int n,m;
char a[MAXN][MAXN];
int b[MAXN][MAXN];
bool visited[MAXN][MAXN];
int ans=0;
int dx[4]={-1,0,0,1};
int dy[4]={0,-1,1,0};
bool inside(int u, int v){
    return u>=1&&u<=n&&v>=1&&v<=m;
}
int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    cin>>n>>m;
    FOR(i,1,n) FOR(j,1,m) cin>>a[i][j];
    FOR(i,1,n) FOR(j,1,m){
        if (a[i][j]=='F') b[i][j]=0;
        else if (a[i][j]=='R') b[i][j]=1;
        else b[i][j]=-1;
    }
    queue<ii> Q[2];
    Q[0].push({1,1});
    visited[1][1]=1;
    int id=0;
    int ans=0;
    while (Q[id].size()){
        ans++;
        while (Q[id].size()){
            ii tmp=Q[id].front();
            Q[id].pop();
            int x=tmp.fs,y=tmp.sc;
            FOR(j,0,3){
                int u=x+dx[j];
                int v=y+dy[j];
                if (!inside(u,v)) continue;
                if (b[u][v]==-1) continue;
                if (!visited[u][v]&&b[u][v]==b[x][y]){
                    visited[u][v]=1;
                    Q[id].push({u,v});
                }
                if (!visited[u][v]&&b[u][v]!=b[x][y]){
                    visited[u][v]=1;
                    Q[id^1].push({u,v});
                }
            }
        }
        id^=1;
    }
    cout<<ans;
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70